These falcons are formidable hunters that prey on other birds (and bats) in mid-flight. Peregrines hunt from above and, after sighting their prey, drop into a steep, swift dive that can top 200 miles an hour (320 kilometers an hour).

Peregrine falcons are among the world's most common birds of prey and live on all continents except Antarctica. They prefer wide-open spaces, and thrive near coasts where shorebirds are common, but they can be found everywhere from tundra to deserts. Peregrines are even known to live on bridges and skyscrapers in major cities.

These birds may travel widely outside the nesting season—their name means "wanderer." Though some individuals are permanent residents, many migrate. Those that nest on Arctic tundra and winter in South America fly as many as 15,500 miles (25,000 kilometers) in a year. Yet they have an incredible homing instinct that leads them back to favored aeries. Some nesting sites have been in continuous use for hundreds of years, occupied by successive generations of falcons.

Peregrine populations were in steep decline during the mid-20th century, and in the United States these beautiful falcons became an endangered species. The birds have rebounded strongly since the use of DDT and other chemical pesticides was curtailed. Captive breeding programs have also helped to boost the bird's numbers in the U.S. and Canada. Now populations are strong in those nations, and in some parts of the globe, there actually may be more peregrines than existed before the 20th-century decline.

Peregrines are favored by falconers, and have been used in that sport for many centuries.